Watch balance staff pivot straightening tool



INVENTOR.

Gregory Romero G. ROMERO June 14, 1955 WATCH BALANCE STAFF PIVOT STRAIGHTENING TOOL Filed Sept. 26. 1952 Fig.

2,716,552 Patented June 14, 1955 WATCH BALANCE STAFF PIVOT STRAIGHTENING TOOL Gregory Romero, Las Vegas, N. Mex.

Application September 26, 1952, Serial No. 311,684

2 (Jlaims. (Cl. 81-6) This invention relates in general to watchmakers tools, and more specifically to a tool for straightening watch balance staff pivots.

The primary object of this invention is to provide an improved watchmakers tool which may be utilized in the straightening of watch balance staff pivots, said tool being adapted to straightening pivots without marring or causing flats on the same.

Another object of this invention is to provide an improved watch balance staif pivot straightening tool which includes means for holding pivots of a watch balance staff in alignment and which permits rotation of a portion of a tool with respect to a bent pivot whereby the pivot is gradually straightened.

Another object of this invention is to provide an improved watchmakers tool for straightening watch balance staff pivots, said tool being of a relatively simple construction and permitting the quick and accurate engagement of a watch balance staff therein whereby the straightening of a pivot thereof is economically feasible.

A further object of this invention is to provide an improved watchmakers tool for straightening watch balance staff pivots, said tool utilizing pivot receiving members including jewels, said jewels being capable of being accurately ground and being advantageous in that they may rigidly engage pivots without marring the same.

A still further object of this invention is to provide a pivot straightening member for a straightening tool, said pivot straightening member including an elongated rod having a jewel seated therein, said jewel having a bore adapted to receive a pivot for straightening the same, said rod being formed of brass or other alloys which are resistant to a dilution of sulfuric acid whereby a broken pivot may be easily and quickly removed from the jewel without damaging either the jewel or the rod.

With these objects definitely in view, this invention resides in certain novel features of construction, combination and arrangement of elements and portions as will be hereinafter described in detail in the specification, particularly pointed out in the appended claims, and illustrated in the accompanying drawings which form a material part of this application and in which:

Figure l is a vertical View of the watch balance staff pivot straightening tool, which is the subject of this invention, and shows the same having engaged therein a watch balance staff in the process of being straightened;

- Figure 2 is a side elevational view of the tool of Figure 1;

Figure 3 is an enlarged fragmentary vertical sectional view taken substantially on the plane indicated by the section line 3-3 of Figure 2 and shows the construction of the lower portion of the tool and the relationship of a pivot of a watch balance staff in its final straightening stage; and

Figure 4 is an enlarged vertical sectional view similar to Figure 3 and shows the initial relationship with a bent pivot with respect to a pivot receiving member of the tool, the pivot receiving member of Figure 4 being of a different size from the pivot receiving member of Figure 3.

Similar characters of reference designate similar or identical elements and portions throughout the specification and throughout the different views of the drawings.

At the present there are many cases of watch balance stafi pivots being slightly bent whereby the watch continues to run, but the pivot is bent sufiiciently to prevent the watch from running properly. In such cases the watch balance staff is normally discarded with the expense of a new staff being passed on to the customer. However, the slight bend in the pivot could be easily straightened with a suitable tool and the staff returned to service in a watch at a minimum cost to the customer. With this thought in mind, there has been provided a watch balance staff pivot straightening tool, which is the subject of this invention, the tool being best illustrated in Figures 1 and 2 of the drawings and referred to in general by the reference numeral 10.

The tool 10 includes a generally C-shaped holder 12 which has spaced parallel end portions 14. The holder 12 is formed of rectangular cross-sectional stock and is generally flat.

The holder 12 is provided with opposed, aligned bores 16 which pass through the ends 14 at substantially right angles to the planes thereof. Disposed in the uppermost of the bores is a first pivot receiving member which is referred to in general by the reference numeral '18. The lowermost of the bores 16 is provided with a second pivot receiving member which is referred to in general by the reference numeral 20. Inasmuch as the pivot receiving members 18 and 20 are identical, only the pivot receiving member 20 will be described in detail. However, it will be understood that the functions of the two pivot receiving members differ in a manner to be set forth in more detail hereinafter.

In order that the pivot receiving members 18 and 20 may be rigidly positioned within their respective bores 16, the holder 12 is provided with a pair of locking screws 22 which communicate with the bores 16 at right angles thereto. As is best illustrated in Figure 3, each locking screw 22 includes a threaded shaft 24 which passes into a threaded bore 26 in the holder 12 adjacent an end 14. The threaded bore 26 communicates with an associated bore 16 and the inner end of the threaded shaft 24 is adapted to engage a pivot receiving member disposed within the associated bore 16. The threaded shaft 24 is provided at its outer end with an enlarged head 28 which is provided with a knurled periphery 30 to facilitate rotation of the same.

Referring once again to Figure 3, it will be seen that the pivot receiving member 20 includes an elongated rod 32 which has formed in the upper end thereof an axially extending bore 34. The bore 34 opens outwardly and has mounted therein an elongated jewel 36.

Referring now to Figure 4 in particular, it is seen that the elongated jewel 36 is provided with an axial bore 38 which is concentric to the bores 16 and 34. In order that the entrance of a pivot into the bore 38 may be facilitated, the outer end of the jewel 36 is provided with a conical counterbore 40 concentric to the bore 38.

In order that the pivot receiving member 20 may be rotated and urged toward the pivot receiving member 18, there is provided an elongated bar which is referred to in general by the reference numeral 42. The bar 42 includes an elongated shaft 44 which may be provided with a suitable handle (not shown) at one end thereof. The other end of the shaft 44 is provided with an enlargement 46 which has an axially extending bore 48 extending partially therethrough and opening out of the free end thereof. The bore 48 is of a size to receive the lower end of the rod 32 and frictionally engage the same.

Referring now to Figure 3 in particular, it will be seen that there is illustrated a watch balance wheel assembly which is referred to in general by the reference numeral 50; The balance wheel assembly includes a balance staff 52 which has mounted thereon a balance wheel 54. The ends of the balance staff 52 are in the form of pivots 56. During the normal use of a watch, the pivots 56 may become bent due to severe shock and have the appearance of the pivot illustrated in Figure 4.

When it is desired to straighten the pivots of the watch balance staff, the watch balance wheel assembly is removed from the watch and the pivots inserted within the bores of the jewels of the pivot receiving members 18 and 20. The pivot receiving member 18 is rigidly positioned within its respective bore 16 by the use of its associated locking screw 22. In the cases where the pivot is only slightly bent, the lower pivot receiving member 2t) may be similarly positioned by its locking screw 22. Then by rotating the balance wheel assembly the pivots will be straightened.

However, in many cases the pivot will be bent to a point whereby it will not fit Within a bore having the same diameter as the bore in the bearing through which it normally runs. In this case it will be readily apparent that pivot receiving members 20 having bores 38 of larger diameters must be initially utilized. As is best illustrated in Figure 4, the bore 38 of the pivot receiving member 20 is of a greater diameter than the normal diameter of the pivot 56, but is of a slightly less diameter than the eccena trio diameter of the bent end of the pivot. By utilizing the bar 42 and permitting the pivot receiving member 29 to be freely positioned Within its bores 16, it will be seen that the upward movement of the pivot receiving member 20 associated with a rotation of the same will slightly straighten the bent pivot 56 and urge the same into the bore 38. Continued upward movement of the pivot receiving member 20 accompanied by further rotation of the same will straighten the pivot 56 to a point whereby its eccentricity is equal to that of the bore 38.

After the bent pivot 56 has been partially straightened in the manner outlined above, the pivot receiving member 20 having a relatively large bore 38 with respect to the diameter of the pivot 56 is removed and a similar pivot receiving member 20 is positioned within the bore 16. The bore through the jewel of the newly positioned pivot receiving member 29 is slightly less than the bore of the first pivot receiving member whereby the bent end of the pivot will engage the conical counterbore 40 thereof. The pivot receiving member 20 is then moved. r

upwardly and rotated through the use of the bar 42 until the bent end of the pivot 56 passes into the bore through its jewel.

It will be seen that by repeating the process to the point whereby the pivot 56 will fit into a bore ina jewel of the diameter of the bore in which it is normally re ceived, it will be completely straightened. Then by applying air to the balance wheel 54 to permit rotation of the same at a high speed any minute eccentricities in the pivot will be eliminated. After being so straightened, the balance Wheel assembly will be replaced in awatch in the normal manner.

It will be understood that if both ends of the watch balance staff have their pivots bent, it will be necessary to duplicate the process for the other pivot.

In some cases, especially when the pivot is badly bent, the pivot will break off during the straightening process and be wedged within the bore in the jewel. Therefore, the rod 32 is formed of brass or other alloy resistant to solution of sulfuric acid so that the pivot receiving member may be submerged in the same and the pivot eroded until it may be easily removed from the jewel. Inasmuch as the rod and jewel are resistant to the action of the dilute sulfuric acid solution, it will be readily apparent that the pivot receiving member will not be damaged.

It will be understood that the pivot receiving member Will have a bore in its jewel of a size to permit an associated pivot to rock freely therein and the thrust taken by a cone portion of the balance staff. In this manner a good pivot at one end of a balance staff will not be damaged during the straightening operation on the bent pivot at the other end thereof.

The operation of this device will be understood from the foregoing description of the details thereof, taken in connection with the above recited objects and drawings. Further description would appear to be unnecessary.

Minor modifications of the device, varying, in minor details from the embodiment of the device illustrated and described here, may be resorted to without departure from the spirit and scope of this invention, as defined in the appended claims.

Having described the invention, What is claimed as new 1. A shaft pivot straightening tool comprising a support having spaced aligned holders, pivot receiving sleeves carried by said holders, means for retaining one of said sleeves against longitudinal movement, the other of said sleeves being mounted for longitudinal and rotary movement, means for urging said other sleeve towards said one sleeve, said means facilitating rotation of said other sleeve, each of said sleeves being provided with an elongated jewel, said jewels having elongated pivot receiving bores, said sleeves being formed of an acid resistant alloy, the jewel of said other sleeve being provided with an elongated conical counterbore to facilitate progressive straightening of a pivot.

2. A shaft pivot straightening tool comprising a support having spaced, aligned holders, pivot receiving sleeves carried by said holders, means for retaining one of said sleeves against longitudinal and rotary movement, means for urging said other sleeve toward said one sleeve, said means facilitating rotation of said other sleeve, each of said sleeves being provided with an elongated jewel, said jewels having elongated pivot receiving bores, the jewel of said other sleeve being provided withv an, e1ongated conical counterbore to facilitate progressive straightening of a pivot.

References Cited in the file of this patent Engel Sept. 9, 1952 

